[Nitro] Idea for improving performance

Sam Smoot ssmoot at gmail.com
Mon Nov 21 18:00:12 EST 2005


Reid Thompson wrote:

> yes,     read 22.1.1. Recovering disk space from
> http://www.postgresql.org/docs/8.1/interactive/maintenance.html -- and
> search the postgresql mail lists.

> an update 'marks' the original tuple for deletion, andinserts a new row
> with the updated data ( it just does it very well and very fast )  :)
> .  That's why vacuum'ing is required --- and why it's being added as an
> 'auto' functionality in 8.1 see 22.1.4. The auto-vacuum daemon

It doesn't mark it for Deletion in the SQL sense. A better way to
describe it might be that it's marked for GarbageCollection. Either
way an Update query combines the existing tuple with the new data. IOW
you don't need to submit the full tuple.

This idea for improving performance is actually very sound, and
implemented by "most" major O/R Mappers around. It's called a
UnitOfWork (http://www.martinfowler.com/eaaCatalog/unitOfWork.html).




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